Sharif Digital Repository

In this research, oscillation in control loop caused by control valve stiction, external harmonic disturbance, poor controller tuning or their combination, is recognized and compensated. In control valve stiction based study, flaws in one of the important modeling methods are described and some modifications are proposed. For diagnosis of oscillation source, signal is decomposed to its fundamental modes and oscillation in each mode is investigated. Then, from the existence of harmonics in decomposed modes, stiction is diagnosed. Also, relation between peak differences in autocorrelation functions of other modes, results to external harmonic disturbance or poor controller tuning as... 

One of the problems in vessels is the marine oscillations that occur due to the collision of sea waves with the vessel. These oscillations in small yachts can cause passengers to seasick upside down and overturn objects in the boat, or in industrial ships can cause problems in the operation of cranes on vessel, and in military vessels can cause errors in targeting weapons and radar systems. The purpose of this research is to design and simulate a robotic compensating table that can actively compensate the vessel fluctuations by using control algorithms in three directions of Roll, Pitch and Heave and create a level that can be used in Medium-sized boats were used to eliminate harmful...